Lithium is becoming the treatment of choice for patients with a manic-depressive illness. Earlier studies in our laboratory suggest that lithium reduces the assimilation of dietary nutrients in vivo. We have proposed an experiment to test this hypothesis in vivo by conducting metabolism studies in the porcine species and collecting the total amount of feces and urine voided. Analysis of fecal and urinary energy by adiabatic calorimetry and nitrogen by micro-Kjeldahl will permit us to determine the specific effect of lithium on absorption and metabolism of these nutrients. Most of the earlier studies on the effect of lithium on gastrointestinal function were conducted in vitro and emphasized the relationship between lithium and sodium. The effect of lithium is related to sodium balance in manic-depressive patients, and sodium is needed for the active transport of glucose and amino acids across the intestinal epithelium. Therefore, these data could offer one explanation for the well known relationship between sodium and lithium and provide basic information on the effect of lithium on gastrointestinal physiology. Additionally, studies supported by this grant will provide data which could have an important clinical application. Very few data are available on the influence of lithium on ovulation rate and practically no data are available on lithium-induced alterations in embryo morphology or viability. However, it is a common practice to remove manic-depressive females from lithium therapy during the first trimester of pregnancy. We propose to investigate the validity of this practice by studying the effect of chronic lithium ingestion on ovulation rate, length of the estrous cycle and ovarian weight in the porcine species. We will also measure the number of live, dead and abnormal embryos,thereby providing the first published information on the direct effect of lithium ingestion on embryo morphology and viability.